Double backflips

Wondering about bit patterns that cause my DSL line to fail, I was curious what order the bits are sent in: LSB-first or MSB-first. According to the published ITU spec:

Outside the LSx serial interfaces data bytes are MSB transmitted first. All serial processing in the ADSL frame (e.g. CRC, scrambling, etc.) shall, however, be performed LSB first, with the outside world MSB considered by the ADSL as LSB

which brought back fond memories of working on network protocols.